EP2512547B1 - Balancing device, external medical functional device, treatment device - Google Patents

Description

The present invention relates to a balancing device according to claim 1. It further relates to an external medical functional device according to claim 7 and a treatment device according to claim 10.

From the EP 0 867 195 B1 Balancing devices are known for balancing volume and / or volume flows of medical fluids such as blood or fluids used during the blood treatment.

The US 4,997,570 A discloses a balancing device with a pump.

The EP 0 623 357 A1 describes a dialyzer with pumps.

The US 3,709,222 A describes a dialyzer with rotating peristaltic pumps.

The EP 0 900 572 A1 discloses a centrifugal pump for conveying a fluid.

The US 2009/095679 A1 discloses pneumatically driven Dialysatverdrängerpumpen.

An object of the present invention is to propose a further balancing device.

This object is achieved by a balancing device for balancing medical fluids, in particular for balancing dialysate, with the features of claim 1.

The balancing device according to the invention has at least one balancing chamber and at least one conveying device for filling the balancing chamber.

Advantageous developments are the subject of the subclaims and embodiments.

In all of the following, the use of the term "may be" or "may have", etc., is synonymous with "is preferably" or "preferably has" and so on.

As used herein, the term "accounting" is understood, in one embodiment, to be a comparison of amounts and / or volumes of medical fluids that are delivered to or removed from a patient or treatment device for treating the patient.

The term "patient" as used herein refers to a human or an animal, whether ill or healthy.

A "balancing chamber" in the sense of the present invention refers to a device which is provided to receive the medical fluids to be balanced - or partial quantities thereof - in an inner or inner volume.

The balancing chamber in one embodiment according to the invention is a chamber which is subdivided into at least two balancing chamber halves or sections by at least one dividing wall or membrane, which can be designed to be displaceable or flexible. At least one of the balancing chamber halves or sections may be provided to receive supplied or fresh medical fluids. At least one more balancing chamber half or another

Balancing section may be provided to receive discharged medical fluids.

The balancing means may comprise more than one balancing chamber, i. e.g. two, three, four or more balancing chambers.

Several, e.g. For example, two balancing chambers can be advantageously used to ensure a continuous flow of medical fluids during balancing.

The balancing chambers may or may not be in fluid communication with each other. The balancing chambers can be filled and / or emptied together or separately.

Each balancing chamber may include (one or more) supply lines for supplied or fresh medical fluids and (one or more) outlet lines for drained spent medical fluids connected to an outlet. In the supply and / or in the discharge lines shut-off valves can be arranged.

Examples of such shut-off valves include actuators that are extendable and / or retractable from a portion of a machine, such as a treatment device. By means of these actuators it may be possible to prevent or release a fluid flow within a fluid system of the medical fluids. Such actuators include those filed in the application filed with the German Patent and Trademark Office by the Applicant of the present application on June 10, 2009 10 2009 024 468.9 entitled "External functional device,

Blatbehandlungsvorrichtung for receiving an external functional device according to the invention, and methods as "phantom valves" designated actuators.

Examples of balancing chambers according to an embodiment of the balancing device of the present invention and their respective function are in the aforementioned EP 0 867 195 B1 the assignee of the present application.

The conveyor may be part of a fluid system in which the medical fluid is present. The conveyor may e.g. be installed or switched to convey the medical fluid in the fluid system. The conveyor may be flowed through in its use of the medical fluid to be balanced.

The fluid system may include conduits, hoses, tubing, channels, chambers, protrusions, devices or spaces or areas for storing or holding or retaining fluids, and control devices for controlling or controlling a flow rate of the fluids and the like.

The fluid system is provided in certain embodiments for a dialysis fluid.

The fluid system, in certain embodiments, is for blood in extracorporeal blood circulation or other fluids intended. The other fluids include citrate and / or calcium solution, water or hydraulic fluid.

The pressure prevailing in the balancing chamber during filling is referred to below as filling pressure. He can be changeable. He can be rising. He can be different in size at different moments.

In one embodiment, a maximum filling pressure of the balancing device according to the invention can be fixed over a set speed of the conveyor. The maximum inflation pressure may be determined by the characteristic of the conveyor, e.g. a pump characteristic, be specified.

In one embodiment, the flow and / or delivery pressure of the conveyor is measured by suitable means. Corresponding means can be configured and provided for this purpose.

The maximum filling pressure for filling the balancing chamber of the balancing device can be predetermined. In one embodiment according to the invention, the maximum filling pressure can be set or adjusted by changing the operating parameters of the conveying device (for example by influencing the rotational speed of a pump).

In a further embodiment according to the invention, the operating parameters of the conveying device (eg by influencing the rotational speed of a pump) can be set or adjusted by changing a magnetic field.

The maximum inflation pressure may, in one embodiment, after it has been reached by the conveyor for a time kept constant or, in another embodiment, fall off. This can be done depending on the preload.

The maximum filling pressure can be achieved, for example, when the balancing chamber is substantially or completely filled or filled with the medical fluid (s) to be balanced.

The maximum inflation pressure may also be reached when a balancing chamber half or balancing chamber section has been substantially or completely filled by operating the conveyor.

In one embodiment of the balancing device according to the invention, the "pressure-limited conveying device" is a conveying device which, after reaching a maximum pressure or filling pressure, does not build up any higher pressure in the interior of the balancing chamber.

The "pressure-limited conveyor" is in another embodiment of the balancing device according to the invention, a pump, the impeller is flowed over upon reaching the maximum filling pressure of the pumped fluid.

The "pressure-limited conveyor" is in a further embodiment of the balancing device according to the invention a conveyor, which can be operated in at least one operating state as a constant pressure source or as a pressure source with constant or approximately constant pressure.

In a further embodiment of the balancing device according to the invention, the "pressure-limited conveying device" is a conveying device which comprises or consists of at least one pump, wherein the pump has no overflow valves and / or bypass lines or is functionally connected to such.

The "pressure-limited conveyor" is in a further embodiment of the balancing device according to the invention, a conveyor which is not connected to a control device for the purpose - and / or provided for this purpose and corresponding configured control device -, a pressure relief of the conveyor depending on a during the filling of the balancing chamber to make the prevailing in this filling pressure.

The "pressure-limited conveyor" is in the balancing device according to the invention, a pump which due to their design no pressure above a predetermined pressure addition - here the filling pressure - builds. It is here in at least one embodiment of the balancing device according to the invention by any other elements, in particular no control, circuit, valves, bypass pressure relief valves, pressure measuring devices and the like, each directly or indirectly supported.

In one embodiment of the balancing device according to the invention, the "pressure-limited conveying device" is a conveying device, in the use of which the balancing chamber filled by it can be assumed to be a volume-stable chamber after reaching a maximum pressure or filling pressure set on the machine side.

The balancing device has, in an embodiment according to the invention, several conveying devices.

In one embodiment of the invention, the balancing means does not comprise overflow valves, bypass lines, controls, circuits, valves, bypass overpressure valves, pressure measuring devices and the like which are suitable and intended or configured for limiting the delivery pressure of the delivery device.

The balancing device has in an embodiment according to the invention no roller pump or gear pump with bypass valve and / or pressure control.

If the balancing device according to the invention has a plurality of conveying devices, they can be configured identically or differently in one embodiment.

In one embodiment of the balancing device according to the invention, this has a plurality of conveyors connected in series. In this way, it may be advantageous to specifically relieve the balancing chamber.

The individual conveying devices are arranged in an embodiment according to the invention of the balancing device in order to run or be operated in the same conveying direction or to convey in the same direction.

In one embodiment of the invention, the conveyors run in different directions or promote in opposite directions. In this case, it may be advantageously possible to deliberately build up pressure and / or limit the volume flow of the medical fluids. This can advantageously contribute to further reducing the forces acting on the balancing chamber. In particular, it may be advantageously possible to reduce or even minimize the forces acting on the balancing chamber and its walls.

In an embodiment according to the invention, at least two conveyors run in the same direction or convey in the same direction. In this case, it may be advantageously possible to selectively reduce pressure. This too can advantageously contribute to further reducing the forces acting on the balancing chamber (discharge of the chamber). In particular, it may be advantageously possible to reduce or even minimize the forces acting on the balancing chamber and its walls.

In one embodiment, a "centrifugal pump" or a centrifugal pump can advantageously provide a high volume flow at low pressures and / or a low flow rate at high pressures.

The centrifugal pump in an embodiment according to the invention is an axial pump with the advantages known to the person skilled in the art in connection with axial pumps.

In a further embodiment according to the invention, the centrifugal pump is a radial pump or a diagonal pump with the advantages known to the person skilled in the art in connection with radial pumps or diagonal pumps.

The maximum pressure of the centrifugal pump - and thus the maximum filling pressure - can be determined by the speed, e.g. be set by means of speed limitation, so that the maximum pressure load on the entire system can be advantageous (very) exactly defined.

The centrifugal pump may have the characteristic that, starting from a certain fluid pressure, e.g. when the balancing chamber is completely filled, an overflow of the impeller or the rotation section occurs. This overflow can result in a pressure limitation in the conveyed fluid, such that the centrifugal pump operates under pressure limitation in the sense of the present invention.

To achieve the pressure limiting the centrifugal pump in one embodiment advantageously requires no support by other components such as control, regulation, valves, etc.

A pressure source is understood according to the invention to mean any fluid delivery device whose output fluid pressure is constant or substantially constant.

In a further preferred embodiment, the conveying device has at least one rotating or rotating section or one rotating section. This is mechanically stored in one embodiment of the invention, in another it is magnetically supported.

The rotation section may be exclusively or additionally magnetically mounted.

The rotation section may be arranged in an interior of the conveyor.

The rotating section may be completely immersed in use by the medical fluids flowing through the conveyor during use.

The rotating section is an impeller or a rotor in one embodiment.

In a further embodiment, the conveying device has at least one rotary section, which is provided and configured to be drivable or operated by means of an external drive magnetically or by means of an electric field.

In a further embodiment, the external drive of the rotary section is configured to be driven mechanically, eg via detachable, fluid-tight couplings.

The term "external drive" as used herein refers to a drive for the rotating section, which may be part of the balancing device but need not be part.

The external drive can be arranged on a device which cooperates with a balancing device according to the invention, such as a treatment device. The external drive may be part of the device.

The magnetic driving force or effect can be achieved by means of one or more magnets. It can be achieved with the help of current-carrying conductors. For example, current-carrying coils can be used.

In one embodiment of the balancing device according to the invention, the conveying device is a magnetically mounted centrifugal pump, as used, for example, in US Pat EP 0 900 572 A1 is disclosed.

Such a magnetically mounted centrifugal pump, like any other magnetically mounted conveyor in the context of the present invention, can offer the advantage that no mechanical and / or electrical interface to the machine is required and / or no fluids have to be transferred from the machine or the treatment device to the pump ,

In a further preferred embodiment, the medical fluid is selected from dialysis fluid, blood, substituate fluid, medicaments, Drug preparations and mixtures or combinations thereof.

In particular, balancing in an embodiment according to the invention on the dialysate side during dialysis is envisaged according to the invention.

In one embodiment of the invention, balancing on the blood side during dialysis is envisaged according to the invention.

Other fluids which may be required to be included in the blood treatment of a patient of interest and / or include solutions or diseased metabolic products of the subject, such as urinary substances, and the like.

In a further preferred embodiment, at least one first conveyor is provided to convey in a first direction. There is further provided at least a second conveyor to promote in a second, the first opposite direction.

The object of the present invention is further achieved by an external medical functional device according to claim 7. All achievable with the balancing device according to the invention advantages can be achieved in certain embodiments undiminished even with the external medical functional device according to the invention, which has at least one balancing device according to the invention.

In one embodiment of the present invention, the external medical device is an external fluid circuit with dialysate and extracorporeal blood circulation, or is designed as a blood or dialysate cassette or combined blood / dialysate cassette. The external medical functional device may e.g. a blood or dialysate cassette or a combined blood / dialysate cassette for dialysis.

In one embodiment of the invention, the external medical device is a disposable, disposable, or disposable product.

In one embodiment of the invention, the external medical device is a disposable cassette.

The disposable cassette can be a hard part. It can be made of a plastic material. The disposable cassette may be made by an injection molding process.

The object of the present invention is further achieved by a treatment device according to claim 10. All achievable with the balancing device according to the invention advantages can be achieved undiminished in certain embodiments, even with the treatment device according to the invention.

The treatment device according to the invention is suitable for the treatment of medical fluids. It is designed to operate at least one balancing device according to the invention.

At least for this purpose, the treatment device may have a control or regulating device. The control or regulating device may be a microprocessor or have such a microprocessor.

In a preferred embodiment of the treatment device according to the invention, the treatment device has a device which is provided and configured to drive the delivery device of the balancing device via a magnetic drive interface.

The device may be, for example, a magnet or a magnetically acting system and / or a current-carrying conductor, such as one or more current-carrying coils, or have these.

The treatment device may be functionally connected to a balancing device according to the invention and / or to an external medical functional device according to the invention.

The treatment device according to the invention comprises in an embodiment according to the invention at least one balancing device according to the invention.

The treatment device according to the invention is firmly connected in one embodiment according to the invention with the balancing device according to the invention.

A repeated use of the firmly connected balancing device according to the invention is provided in an embodiment according to the invention.

The treatment device according to the invention is a hemodialysis device in one embodiment according to the invention.

The treatment device further includes, in certain embodiments, further means or is provided for coupling therewith. These include, for example, an extracorporeal blood circulation, control or regulating devices for triggering the execution of a medical treatment, devices for monitoring and / or displaying a balance of the medical fluids used and / or circulated during a medical treatment, devices for displaying or displaying states, and / or parameters of the medical treatment or the balance, such as screens and the like, means for operating or driving one or more components of the treatment device, such as keyboards and the like, for example to initiate medical treatment, and the like.

In one embodiment of the invention, the treatment device is a blood treatment device.

Examples of blood treatment methods include dialysis methods such as hemodialysis, especially by ultrafiltration, hemodiafiltration, peritoneal dialysis, automatic peritoneal dialysis, and the like. The blood treatment device may be designed to carry out these methods.

Not least in the case of peritoneal dialysis, the balancing device according to the invention can advantageously be used to determine the volume the dialysis fluid, which is passed into the peritoneal region of the patient and / or from there out of the patient, are used. In this case, for example, both balancing chamber halves of a two-part balancing chamber of the balancing device can be filled alternately with fresh dialysis fluid (when the dialysis fluid enters the abdominal cavity of the patient) and / or with used dialysis fluid (when removing the dialysis fluid from the patient's abdominal cavity). The volumes and / or quantities of the medical fluids, eg the dialysis fluid, which are of interest in a balancing can be determined, for example, via the number of fillings of the balancing chamber.

A method comprises balancing at least one medical fluid using at least one balancing device according to the invention or at least one external medical functional device according to the invention or at least one treatment device according to the invention.

One method comprises filling a balancing chamber by means of at least one conveying device and operating the conveying device in at least one operating state as a constant pressure source.

In order to operate the conveyor in the desired operating state as a constant pressure source, a certain speed of the conveyor can be set, in which a fixed or fixed or predetermined pressure difference over the conveyor can be set.

The present invention proposes a balancing device in which the delivery device is operated as a constant pressure source after filling the balancing chamber (s).

The constant pressure source can advantageously help to ensure a maximum filling pressure within the balancing chamber. The structural requirements of the balancing chamber can thus be lower.

In general, a balancing accuracy may depend primarily on the pressure fluctuations between two filling operations, which can be explained by the fact that the switching operation for terminating a filling process is subject to slight fluctuations, and that the increase of the filling pressure or the chamber internal pressure considerably increases towards the end of the filling.

It is also known that a balancing chamber i.a.R. not pressure stable. For this reason, the filling volume may change.

Since the medical fluids introduced into the balancing chamber by means of the conveying device can displace the fluids present in the balancing chamber to the same extent or at the same speed or rate, it may be advantageously possible to produce a constant or uniform volume and / or volumetric flow of the fluids to be balanced to reach.

Since a pressure difference for operating the balancing chamber can be set in an advantageously simple manner via the rotational speed and / or the maximum delivery pressure of the delivery device, the pressure-limited delivery device can predetermine an advantageously precisely controllable balancing chamber pressure (also dynamically controllable) during the balancing of the medical fluids.

An adverse increase in pressure and / or pressure fluctuations of the balancing chamber can be advantageously avoided. An undesirable volume expansion or change of the balancing chamber can be advantageously prevented.

In this way, it may be advantageously possible to improve a quantity and / or volume accuracy of a balance.

This may also, for example, beneficially contribute to reducing the volume of fluid that can be delivered to a patient during a treatment, e.g. an ultrafiltration during a dialysis treatment, is withdrawn over the dialysis filter membrane, to determine precisely and / or set to the desired rate by the treating physician. The safety and possibly also the compatibility of a blood treatment can be further improved so advantageous.

Thus, it may be advantageously possible to prevent a false balance, with a false balance can accumulate over the duration of a blood treatment session, for example. If the balancing has an effect on the treatment carried out, the balancing device according to the invention, in at least one embodiment, can be improved Balancing accuracy advantageous for improved and / or safer treatment - eg by a more appropriate setting an ultrafiltration rate - lead.

The balancing chamber of the balancing device according to the invention can be advantageously used as a pressure-limited volumetric balancing chamber with sufficient strength.

In complicated constructions, such as struts or reinforced plastic materials or the like, with which a sufficient strength must be ensured in the prior art, can be advantageously dispensed with when using the balancing device according to the invention. The construction of the balancing device according to the invention can thus be advantageously simplified due to the intended pressure limitation by means of the conveyor.

A support of walls of the balance chamber to fixed structures of the treatment device is not required. The application possibilities of the balancing device have become broader without losing their functional accuracy.

In addition, the conveyor in the balancing device according to the invention can advantageously manage without the use of sensors and / or overflow valves and / or bypass overpressure valves, in particular for the purpose of limiting the pressure in an interior of the balancing chamber, and the like. Thus, it may also be advantageously possible to simplify the operation of the balancing device. The conveyor device can be designed simpler.

In this way, dimensions of the balancing device and the space required for the balancing can be kept advantageously low.

By a magnetic mounting of the conveyor, the construction of the conveyor can be advantageously simplified. Thus, it may be advantageously possible to dispense with mechanical components, such as bearings and the like, and in this way advantageously ensure low wear of the components and / or low particle abrasion. As a result, heating of the conveyor device or of the balancing device can advantageously also be avoided or reduced.

Furthermore, the conveying device of the balancing device according to the invention can advantageously have a low tendency to cavitate.

Another advantage may be a low noise during use of the balancing device according to the invention.

Since the pressure of the conveyor does not increase even with a sustained flow after completion of the filling of the balancing chamber, can be bypassed advantageous to have to shut down the conveyor at full, ie substantially or completely filled, balancing chamber. For example, a fluid flowing through the centrifugal pump can overflow a rotary section of the centrifugal pump. In this way, a good flushability (and Umspülbarkeit) of the conveyor can be ensured with a directed flow in the space traversed by the centrifugal pump.

The magnetic drive interface for operating the conveyor or a rotation section thereof can advantageously provide a non-contact and / or seal-free drive of the conveyor. In this way, it may be advantageously possible to dispense with open interfaces between the balancing device and the treatment device.

Thus, it may be advantageous to ensure a particularly safe operation of the balancing device. A - although only extremely small - risk of contamination of the medical fluids can thus be advantageously reduced and even completely excluded.

The balancing device according to the invention can advantageously be described as disposable, i. used as disposables for single use. Since the conveyor can be provided as an integral part of the disposable, it can be discarded together with the disposable, whereby the safety and hygiene of medical treatment can be advantageously further improved.

The use of centrifugal pumps, in certain embodiments, has the advantage of inherently limiting the pressure upon occlusion downstream of the pump, as compared to the pressure controlled tubular roller, gear or peristaltic pumps. The pressure built up there can be easily adjusted by the speed. A pressure-controlled hose roller pump requires at least one pressure sensor with control circuit; a hose roller pump with

Overpressure bypass valve must be calibrated to exactly the allowed pressure. By using centrifugal pumps, the balancing device according to the invention is therefore less complicated in certain embodiments.

Fig. 1

zeigt schematisch vereinfacht eine erfindungsgemäße Bilanziereinrichtung während eines ersten Arbeitstaktes;

Fig. 2

zeigt als Diagramm einen Druckverlauf in Abhängigkeit der Zeit während einer Bilanzierkammerfüllung;

Fig. 3

zeigt als Diagramm eine Druckdifferenz zwischen dem Pumpenaus- und dem Pumpeneinlass einer Zentrifugalpumpe in Abhängigkeit vom Volumenstrom;

Fig. 4

zeigt schematisch vereinfacht die erfindungsgemäße Bilanziereinrichtung der Fig. 1 während eines zweiten Arbeitstaktes;

Fig. 5

zeigt schematisch vereinfacht die erfindungsgemäße Bilanziereinrichtung der Fig. 1 mit zwei weiteren, der Bilanzierkammer nachgeschalteten Zentrifugalpumpen;

Fig. 6

zeigt schematisch vereinfacht die erfindungsgemäße Bilanziereinrichtung mit der Bilanzierkammer, Ventilen, Zentrifugalpumpen, wobei eine der nachgeschalteten Zentrifugalpumpen in einer anderen Richtung dreht;

Fig. 7

zeigt schematisch vereinfacht eine Zentrifugalpumpe mit magnetischer Lagerung und magnetischem Antrieb;

Fig. 8

zeigt schematisch vereinfacht eine erfindungsgemäße Behandlungsvorrichtung mit Bilanziereinrichtung und einer externer medizinischer Funktionseinrichtung; und

Fig. 9

zeigt schematisch vereinfacht eine erfindungsgemäße Bilanziereinrichtung einer weiteren Ausführungsform während eines ersten Arbeitstaktes.

In the following, the present invention will be described by way of example with reference to the accompanying drawings. In the drawing, like reference characters designate like or identical components. The following applies:

Fig. 1

shows schematically simplified a balancing device according to the invention during a first power stroke;

Fig. 2

shows a diagram as a pressure curve as a function of time during a balancing chamber filling;

Fig. 3

shows a diagram of a pressure difference between the Pumpenaus- and the pump inlet of a centrifugal pump as a function of the flow rate;

Fig. 4

shows schematically simplified the balancing device of the invention Fig. 1 during a second work cycle;

Fig. 5

shows schematically simplified the balancing device of the invention Fig. 1 with two further centrifugal pumps connected downstream of the balancing chamber;

Fig. 6

shows schematically simplified the balancing device according to the invention with the balancing chamber, valves, centrifugal pumps, wherein one of the downstream centrifugal pumps rotates in a different direction;

Fig. 7

shows schematically simplified a centrifugal pump with magnetic bearing and magnetic drive;

Fig. 8

schematically shows a simplified treatment device according to the invention with balancing device and an external medical functional device; and

Fig. 9

schematically shows a simplified balancing device according to the invention a further embodiment during a first power stroke.

The balancing device is described below by way of example as part of a blood treatment device for dialysis. It is intended to balance the dialysis fluid supplied to and discharged from a patient. In principle, however, it can also be provided to balance the blood of the patient.

Fig. 1 shows a balancing device 100 according to the present invention with a balancing chamber. 1

As in Fig. 1 1, the balancing chamber 1 is divided into a first balancing chamber half 3a and a second balancing chamber half 3b. In principle, however, the balancing chamber does not have to be essentially two or three be divided completely equal balancing chamber halves.

The first balancing chamber half 3a is separated from the second balancing chamber half 3b by a fluid-impermeable membrane 5.

The first balancing chamber half 3a is filled with a stream 7a of a dialysis fluid via a hose 9a. A valve 11a is located in the open position by means of an actuating mechanism 13a.

The conveyor may be a centrifugal pump. As in Fig. 1 is shown, the first chamber half 3a is filled by means of a centrifugal pump 15a.

The valve 11a can be designed as a hose clamp (or generally as a squeezing mechanism). Such a hose clamp can be opened and closed by an electrically controlled actuator. This has the advantage that the medical fluid has essentially only contact with the hose 9a, but not with parts of the valve 11a or the adjusting mechanism 13a. This can advantageously contribute to reducing the risk of contamination for the medical fluids.

A second stream 7b of the dialysis fluid is discharged through a hose 9b from the second balancing chamber half 3b. A valve 11b is also in the open position, mediated by an adjusting mechanism 13b.

The second balancing chamber half 3b can be emptied. The discharge or removal of dialysis fluid from the second balancing chamber half 3b can be carried out simultaneously with the introduction or introduction of dialysis fluid into the first balancing chamber half 3a.

Valves 11c and 11d are as in FIG Fig. 1 shown, in each case closed by means of the corresponding adjusting mechanisms 13c and 13d. No fluid is delivered in hoses 9c and 9d.

Fig. 2 shows a diagram with a pressure curve 17 during a balancing chamber filling as a function of time.

An initial pressure at t = 0 corresponds to a pressure with which in Fig. 1 , which will also be referred to hereinafter, the flow 7a of the dialysis fluid is introduced through the tube 9a after opening the valve 11a in the first balancing chamber half 3a. So that the flow 7b of dialysis fluid can flow out of the second balancing chamber half 3b through the tube 9b, the valve 11b should be open.

While the first balancing chamber half 3a is filled and the second balancing chamber half 3b is emptied, the pressure in the balancing chamber 1 initially drops.

When the first balancing chamber half 3a is filled, the pressure increases. A final pressure 18, which corresponds to the end point of the pressure curve at balance chamber filling 17 and thus the maximum filling pressure, may depend on the pressure which the centrifugal pump 15a applies. This pressure can in turn depend on several parameters of the centrifugal pump Depending on the construction principle of the centrifugal pump (radial, axial, Diagonal pump, impeller shape, diameter of the impeller, etc.) and / or the set speed of the centrifugal pump 15a and thus the set operating point. Further, the discharge pressure may depend on the preload of the centrifugal pump 15a, that is, the pressure applied to a dialyzate inlet of the centrifugal pump 15a.

Fig. 3 shows a diagram with a pressure difference .DELTA.P between the Pumpenaus- and the pump inlet of a centrifugal pump 15a (ordinate) as a function of the volume flow Q of medical fluids (abscissa).

In a characteristic curve 19 of an ideal pressure source, which is indicated for comparison, the pressure difference .DELTA.P is independent of the volume flow Q. The height or the extent of the pressure difference .DELTA.P depends inter alia on the set speed of a centrifugal pump.

The actual pressure curves (ΔP, Q) usually deviate from the ideal characteristic curve. A possible pressure curve of a characteristic curve for a pressure-limited conveying device such as the centrifugal pump 15a of the balancing device 100 according to the invention Fig. 1 shows the characteristic curve 21 of a centrifugal pump. It can be seen that a good approximation of the pressure curve to the ideal characteristic curve can be achieved by means of the centrifugal pump 15a. Fig. 3 also shows that the centrifugal pump 15a can be understood as a pressure-limited conveying device in the sense of the present invention: the pump outlet pressure does not increase any further after reaching a certain pressure despite increasing volume flow.

Fig. 4 shows the balancing device 100 of Fig. 1 during a second work cycle. The second work cycle can correspond to the first work cycle Fig. 1 follow.

A stream 7c of dialysis fluid is conveyed in the second power stroke by a centrifugal pump 15c through the hose 9c into the second chamber half 3b. At the same time, a stream 7d of dialysis fluid from the first chamber half 3a is emptied.

Fig. 5 shows the balancing device 100 of Fig. 1 with two additional, the balancing chamber 1 downstream centrifugal pumps 15b and 15d.

The in the inventive balancing device 100 of Fig. 5 arranged centrifugal pumps 15a-d promote all in the same conveying direction, as with the left (based on the representation of Fig. 5 ) pointing pump arrow heads is indicated.

With the help of the downstream centrifugal pumps 15b and 15d, the emptying of the two chamber halves 3a and 3b can be supported. This may be advantageous, for example, to achieve maximum pressure (see Fig. 2 the end point 18 of the curve of the pressure curve) in the balancing chamber 1 to reduce or keep low. Low pressures in the balancing chamber 1 can in turn advantageously contribute to simplify the construction (such as a lower rigidity, lower material thicknesses, etc.) of the balancing device 100 as stated above. The latter can be advantageous in particular in one embodiment of the balancing device 100 as part of a disposable.

Fig. 6 shows the balancing device 100 with the balancing chamber 1 similar to in Fig. 5 with the difference that the centrifugal pump 15b is provided and configured to also run in a different direction or in opposite directions, as with the left (referring to the illustration of Fig. 6 ) pointing pump head is indicated.

The centrifugal pump 15b operates, when it runs in the opposite direction of rotation, as a pressure reducer, in particular as an adjustable pressure reducer.

In the embodiment of the Fig. 6 For example, the inlet and outlet of the centrifugal pump 15b may be reversed.

An "exchange" of inlet and outlet can be done in various ways. Examples of this are a reverse installation of the centrifugal pump, a provision of appropriately arranged and controlled valves and the like.

With appropriately arranged and controlled valves, these can preferably be actuated by actuators of a dialysis machine via a flexible membrane, e.g. by impressing and / or releasing the relevant fluid paths.

The direction reversal can be provided in addition or alternatively. The considered conveyor may be provided and configured to operate in one or two opposite directions.

Fig. 7 shows a centrifugal pump 15a with an impeller 25 as a rotating section, a rotor 27, coils 29 and a stator 31. The centrifugal pump 15a has a housing 32 with an inlet and an outlet (indicated by arrows in FIG Fig. 7 recognizable as such).

The centrifugal pump 15a is flowed through in the flow direction shown. The drive of the impeller 25 is effected by a circulating electromagnetic field, generated by means of driving the coils 29 of the stator 31st

In the impeller 25 impeller magnets or at least ferromagnetic materials may be integrated.

The bearing of the impeller 25 can then take place on the one hand by means of the impeller magnets and on the other hand by means provided outside of the centrifugal pump magnets. The magnets may be arranged circumferentially in the same rotational movement as the impeller 25. Instead of the rotating magnets or in addition thereto, a rotating electromagnetic field in a coil arrangement store the impeller 25 and fix it in a stable circumferential position. Although not shown in the figures, this embodiment is also included in the invention.

Fig. 8 schematically shows a simplified balancing device 100 according to the invention and a treatment device 300 according to the invention with a dialyzer 33 with a blood inlet 33a and a blood outlet 33b, and other elements.

Fig. 9 shows in reference to the Fig. 1 schematically simplifies an inventive balancing a another embodiment during a first power stroke. It can be seen that the centrifugal pump 15b conveys in the opposite direction to the conveying direction of the centrifugal pump 15a. By means of this embodiment of the conveying devices pumping in opposite directions, an optionally too high inlet pressure can advantageously be counteracted or reduced. This may be the case when the dialysate is made from reverse osmosis water (RO) and concentrates. The RO water connection can have such a high line pressure that the balancing device could be damaged by it.

Claims (12)

1. A balancing unit (100) for medical fluids comprising

   - at least one balancing chamber (1) and

   - at least one conveying means for filling the balancing chamber (1),
   wherein the conveying means is a pressure limited conveying means,

   characterized in that the conveying means is a centrifugal pump which, due to its type, does not build up a pressure above a predetermined pressure, without being supported by further elements.
2. The balancing unit (100) according to claim 1, wherein the conveying means comprises at least one rotational section provided and designed for being actuated magnetically by means of an external actuator or by means of an electrical field.
3. The balancing unit (100) according to claim 2, wherein the external actuator is not part of the balancing unit.
4. The balancing unit (100) according to anyone of the preceding claims, wherein the medical fluid is selected from blood, dialysis liquid, substituate liquid, drugs, drug preparations as well as mixtures or combinations thereof.
5. The balancing unit (100) according to anyone of the preceding claims, wherein the conveying means comprises at least one first conveying means provided to convey in a first direction and at least one second conveying means provided to convey in a second direction opposite to the first direction.
6. The balancing unit (100) according to anyone of the preceding claims, wherein the conveying means comprises at least one first conveying means provided to convey in a first direction and at least one second conveying means provided to convey in the first direction, too.
7. An external medical functional means (200) comprising at least one balancing unit (100) according to anyone of claims 1 to 6.
8. The external medical functional means (200) according to claim 7, configured as an external or extracorporeal blood circuit or blood cassette.
9. The external medical functional means (200) according to claim 7 or 8, configured as a disposable or one-way article for insertion in a blood treatment apparatus, wherein the functional means (200) comprises at least one pressure limited conveying means and at least one integrated balancing chamber which is separated into two chamber sections by means of one or at least one flexible membrane.
10. A treatment apparatus (300) for treating medical fluids comprising at least one balancing unit (100) according to anyone of claims 1 to 6.
11. The treatment apparatus (300) according to claim 10, functionally connected with a balancing unit (100) according to anyone of claims 1 to 6 and/or with an external medical functional means (200) according to claims 7 to 9.
12. The treatment apparatus (300) according to anyone of claims 10 to 11, configured as a blood treatment apparatus, in particular as a hemodialysis machine.

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